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Articles 31 - 60 of 107
Full-Text Articles in Geology
Effect Of Oxidative Breakers On Organic Matter Degradation, Contaminant Mobility And Critical Mineral Release During Shale-Fracturing Fluid Interactions In The Marcellus Shale, Shaun Donmoyer
Graduate Theses, Dissertations, and Problem Reports (ETD)
Production of oil and gas from organic-rich shale formations has become viable through advancements in multi-stage hydraulic fracturing. The decline of shale gas production after the initial days of fracturing operations coupled with falling oil and gas prices, has pushed industry operators to use new chemical additives as an attempt to increase hydrocarbon production. The implementation of highly reactive fracturing fluids that include strong oxidizing agents, pose as a potential solution to increase well productivity. Strong oxidizing chemicals commonly known in fracturing operations as breakers, are used to improve the viscosity of gel-based fluids after the proppant is transported into …
Application Of 3d Seismic Signal And Geomechanical Attributes For Subsurface Fracture Characterization: A Case Study In Clearfield County, Central Pennsylvania, Iman F. Zulkapeli
Application Of 3d Seismic Signal And Geomechanical Attributes For Subsurface Fracture Characterization: A Case Study In Clearfield County, Central Pennsylvania, Iman F. Zulkapeli
Graduate Theses, Dissertations, and Problem Reports (ETD)
Hydrocarbon exploration in unconventional reservoirs is highly risky due to the nature of the reservoirs and the variability in fractures and reservoir geomechanical properties in the subsurface. The reservoir needs to be fully characterized to avoid any complication such as frac hit, wellbore failure, blowout, or even a dry hole. The Clearfield reservoir produces an exceptionally low amount of gas, compared to the neighboring region in the proximity, which has been poorly understood. This raises the question as to what causes the reservoir to have low productivity.
This study focuses on the natural fracture characterization using high-quality 3D seismic signal …
Independent, Semi-Automated Classification Of Petrographic Features In Volcanic Rocks Using Fiji And Weka, Holly Danielle Pettus
Independent, Semi-Automated Classification Of Petrographic Features In Volcanic Rocks Using Fiji And Weka, Holly Danielle Pettus
Graduate Theses, Dissertations, and Problem Reports (ETD)
Traditional methods of collecting quantitative petrographic data from thin sections (modal mineralogy, size distribution, shapes, etc.) are time- and labor-intensive, and rarely have sample sizes adequate to statistically describe complex rocks (i.e. volcanic rocks). Although manual counting and measurements are now routinely supplemented by digital image analysis, the majority of quantitative petrographic studies still go through a manual digitization stage where object classes are traced before further analyses. This is a major rate-limiting step that reproduces the same problems of small n-values resulting from significant effort. We have valuated the potential and limitations of using the Trainable Weka Segmentation (TWS) …
Reservoir Characteristics And Lateral Variability Of The Marcellus Formation At The Allegheny Mountain Front, Bruno J. Abersold
Reservoir Characteristics And Lateral Variability Of The Marcellus Formation At The Allegheny Mountain Front, Bruno J. Abersold
Graduate Theses, Dissertations, and Problem Reports (ETD)
The Marcellus Formation, a large shale gas reservoir located within in the Appalachian basin, produces the energy that fuels the economy across the United States. Well data and rock core for the Coastal 1H well, found in Fayette County, Pennsylvania, provides the basis to understand reservoir characteristics and depositional processes of the Marcellus Formation across the basin. The well is located near along the eastern edge of the productive fairway and adjacent to the Allegheny mountain front. We used characteristics, such as total organic carbon (TOC), geomechanical properties, and lithology, to integrate with ten other available wells across the basin. …
Petrographic And Core Analysis Of The Jurassic Norphlet Formation: A Case Study In The Lithofacies Control Of Diagenesis And Porosity In The Flomaton Field, Al, Jarrett Thomas Smith
Petrographic And Core Analysis Of The Jurassic Norphlet Formation: A Case Study In The Lithofacies Control Of Diagenesis And Porosity In The Flomaton Field, Al, Jarrett Thomas Smith
Graduate Theses, Dissertations, and Problem Reports (ETD)
This study includes a sedimentologic and petrographic study of cores and thin-sections from the Jurassic Norphlet Formation in the Flomaton Field in southern Alabama to define a specific paragenetic history of each facies encountered and to identify key controls on reservoir quality. Eolian dune, nearshore, sand flat, and wadi facies were likely encountered in Norphlet core and thin-section samples that displayed a high degree of heterogeneity between them in terms of porosity, grain contacts, cement abundance/type, intergranular volume, and overall diagenetic processes. These distinct petrographic differences suggest that the paragenesis in the Flomaton Field is primarily facies controlled. The eolian …
The Fold Illusion: The Origins And Implications Of Ogives On Silicic Lavas, Graham Dm Andrews, Stuart Kenderes, Alan Whittington, Shelby L. Isom, Sarah Brown, Holly Danielle Pettus, Brenna Cole, Kailee Gokey
The Fold Illusion: The Origins And Implications Of Ogives On Silicic Lavas, Graham Dm Andrews, Stuart Kenderes, Alan Whittington, Shelby L. Isom, Sarah Brown, Holly Danielle Pettus, Brenna Cole, Kailee Gokey
Faculty & Staff Scholarship
Folds on the surfaces of mafic lavas are among the most readily recognized geological structures and are used as first-order criteria for identifying ancient lavas on Earth and other planetary bodies. However, the presence of surface-folds on the surface of silicic lavas is contested in this study and we challenge the widely accepted interpretation that silicic lava surfaces contain folds using examples from the western United States and Sardinia, Italy. We interpret the ridges and troughs on their upper surfaces, typically referred to as ‘ogives’ or ‘pressure ridges’, as fracture-bound structures rather than folds. We report on the absence of …
Teaching With Digital 3d Models Of Minerals And Rocks, Graham Dm Andrews, Gabrielle Labishak, Sarah Brown, Shelby L. Isom, Holly Danielle Pettus, Trevor Byers
Teaching With Digital 3d Models Of Minerals And Rocks, Graham Dm Andrews, Gabrielle Labishak, Sarah Brown, Shelby L. Isom, Holly Danielle Pettus, Trevor Byers
Faculty & Staff Scholarship
The disruption to geoscience curricula due to the COVID-19 pandemic highlights the difficulty of making mineral and rock samples accessible to students online rather than through traditional lab classes. In spring 2020, our community had to adapt rapidly to remote instruction; this transition amplified existing disparities in access to geoscience education but can be a catalyst to increase accessibility and flexibility in instruction permanently. Fortunately, a rich collection of 3D mineral and rock samples is being generated by a community of digital modelers (e.g., Perkins et al., 2019).
Volcanic Record Of The Arc-To-Rift Transition Onshore Of The Guaymas Basin In The Santa Rosalía Area, Gulf Of California, Baja California, Graham Dm Andrews
Volcanic Record Of The Arc-To-Rift Transition Onshore Of The Guaymas Basin In The Santa Rosalía Area, Gulf Of California, Baja California, Graham Dm Andrews
Faculty & Staff Scholarship
The Gulf of California is an archetype of continental rupture through transtensional rifting, and exploitation of a thermally weakened arc to produce a rift. Volcanic rocks of central Baja California record the transition from calcalkaline arc magmatism, due to subduction of the Farallon plate (ca. 24–12 Ma), to rift magmatism, related to the opening of the Gulf of California (<12 Ma). In addition, a suite of postsubduction rocks (<12 Ma), referred to as “bajaites,” are enriched in light rare-earth and other incompatible elements (e.g., Ba and Sr). These are further subdivided into high-magnesian andesite (with 50%–58% SiO2 and MgO >4%) and adakite (>56% SiO2 and MgO <3%). The bajaites correlate spatially with a fossil slab imaged under central Baja and are inferred to record postsubduction melting of the slab and subduction-modified mantle by asthenospheric upwelling associated with rifting or slab breakoff. We report on volcanic rocks of all three suites, which surround and underlie the Santa Rosalía sedimentary rift basin. This area represents the western margin of the Guaymas basin, the most magmatically robust segment of the Gulf of California rift, where seafloor spreading occurred in isolation for 3–4 m.y. (starting at 6 Ma) before transtensional pull-apart basins to the north and south ruptured the continental crust. Outcrops of the Santa Rosalía area thus offer the opportunity to understand the magmatic evolution of the Guaymas rift, which has been the focus of numerous oceanographic expeditions.
We describe 21 distinct volcanic and hypabyssal map units in the Santa Rosalía area, using field characteristics, petrographic data, and major- and trace-element geochemical data, as well as zircon isotopic data and …
3%).>12>Paleohydrology And Machine-Assisted Estimation Of Paleogeomorphology Of Fluvial Channels Of The Lower Middle Pennsylvanian Allegheny Formation, Birch River, Wv, Oluwasegun O. Abatan, Amy Weislogel
Paleohydrology And Machine-Assisted Estimation Of Paleogeomorphology Of Fluvial Channels Of The Lower Middle Pennsylvanian Allegheny Formation, Birch River, Wv, Oluwasegun O. Abatan, Amy Weislogel
Faculty & Staff Scholarship
Rivers transport sediments in a source to sink system while responding to allogenic controls of the depositional system. Stacked fluvial sandstones of the Middle Pennsylvanian (Desmoinesian Stage, ∼310–306 Ma) Allegheny Formation (MPAF) exposed at Birch River, West Virginia exhibit change in sedimentary structure and depositional style, reflecting changes in allogenic behavior. Paleohydrologic and numerical analysis were used to quantify geomorphological and paleohydrologic variations reflected by MPAF fluvial deposits with the goal of understanding the controls on resulting fluvial sandstone architecture in these different systems. Channel body geometry, sedimentary structures, and sandstone grain size distribution were used to reconstruct the paleoslope …
The Transition From Planar To En Echelon Morphology In A Single Vein In Shale: Insights From X-Ray Computed Tomography Scanning, Graham Dm Andrews, Sarah R. Brown, Johnathan Moore, Dustin Crandall, Paige Mackey
The Transition From Planar To En Echelon Morphology In A Single Vein In Shale: Insights From X-Ray Computed Tomography Scanning, Graham Dm Andrews, Sarah R. Brown, Johnathan Moore, Dustin Crandall, Paige Mackey
Faculty & Staff Scholarship
En echelon fractures and veins are among the most common and distinctive geological structures, yet their three-dimensional forms and relationships to surrounding structures are commonly unclear. X-ray computed tomography (CT) offers an unrivaled ability to examine structures within rocks in three dimensions, and it is applied here to a sample of drill core from the Marcellus Shale of southwestern Pennsylvania (USA). CT images yield qualitative and quantitative data on the transition from a pyrite-rich planar vein to an en echelon veinlet array, and on the heterogeneity of veinlets within the array. Using a combination of three- and two-dimensional images, geometric …
Household Water Security: An Analysis Of Water Affect In The Context Of Hydraulic Fracturing In West Virginia, Appalachia, Bethani Turley, Martina Angela Caretta
Household Water Security: An Analysis Of Water Affect In The Context Of Hydraulic Fracturing In West Virginia, Appalachia, Bethani Turley, Martina Angela Caretta
Faculty & Staff Scholarship
Hydraulic fracturing has been booming in the last decade in the United States. While natural gas extraction and production has improved the national energy security, it has raised questions around the water security of those communities where extraction is taking place. Both scientists and residents are concerned about hydraulic fracturing’s impacts on surface- and groundwater, especially regarding how hydraulic fracturing impacts residents’ access to safe household well water. In the past decade, the Marcellus Shale has been developed in Northwestern West Virginia, yet the human geography dimensions of oil and gas extraction in West Virginia remain to be investigated. This …
Physical And Chemical Properties Of Clastic Sediments From Two Caves In The Northern Karst Region Of Puerto Rico, Autum R. Downey
Physical And Chemical Properties Of Clastic Sediments From Two Caves In The Northern Karst Region Of Puerto Rico, Autum R. Downey
Graduate Theses, Dissertations, and Problem Reports (ETD)
Geochemical properties and organic characteristics are essential to understanding the general depositional dynamics of a cave. Most work on clastic cave sediments focuses on physical properties of sediments. Little work has been done on bulk organic matter and geochemical properties.
This project reports physical and geochemical characterization of cave sediments from two caves in the northern karst region of Puerto Rico: El Tallonal Cave and Cueva Clara. Core and grab samples were collected and analyzed for particle size, total organic carbon, total nitrogen, organic matter characteristics using fluorescence spectroscopy, and major and minor elements using X-ray fluorescence (XRF). The sediments …
Paleoecological Successions From Shallow-Marine Depositional Environments In Upper Silurian Carbonate Rocks Of Blair County, Pennsylvania, Shadya El-Ashkar
Paleoecological Successions From Shallow-Marine Depositional Environments In Upper Silurian Carbonate Rocks Of Blair County, Pennsylvania, Shadya El-Ashkar
Graduate Theses, Dissertations, and Problem Reports (ETD)
Studies of paleoenvironment and paleoecology are important for investigating relationships between the different environmental and biological variables that influenced biodiversification patterns during the Silurian Period. The mixed carbonate and siliciclastic rocks of the Bloomsburg and Mifflintown Formations in central Pennsylvania represent transitions between carbonate ramp and deltaic settings. The goal of this study was to assess changes in depositional environment and paleoecology of an undescribed Bloomsburg/Mifflintown locality in Bellwood, Pennsylvania. In central Pennsylvania, the interfingered relationship of mixed carbonate and siliciclastic mudstones of the Mifflintown Formation with red fine-grained sandstones and shales of the Bloomsburg Formation presented challenges for deciphering …
Alluvial Fans, Loess Plains, Lakes, And Distributive Fluvial Systems: Depositional Systems Of The Permian-Triassic Red Beds And Evaporites Of Wyoming (Usa), Jonathan Knapp
Graduate Theses, Dissertations, and Problem Reports (ETD)
The end-Permian ecological crisis was a period of warming and aridity reaching extreme levels by the end Permian and not recovering before the Middle Triassic. The Permian Goose Egg Formation and the Chugwater Group’s Early Triassic Red Peak Formation and Middle Triassic Alcova Limestone are a continuous or nearly continuous succession of rocks deposited during this warm, arid time in Wyoming. Comprised of red beds, evaporites, and rare carbonates, these rocks have not been subjected to detailed sedimentological investigations in the modern era. Previous interpretations of marine and marginal marine deposition have largely been based on the laterally extensive nature …
Mapping Surficial Geology In The New River Gorge National River And Bluestone National Scenic River, West Virginia, Using Lidar-Derived Digital Elevation Data, Marla K. Denicola
Mapping Surficial Geology In The New River Gorge National River And Bluestone National Scenic River, West Virginia, Using Lidar-Derived Digital Elevation Data, Marla K. Denicola
Graduate Theses, Dissertations, and Problem Reports (ETD)
The purpose of this thesis was to determine if the surficial geology of Bluestone National Scenic River (BLUE) and New River Gorge National River (NERI), two areas of similar geology, can be mapped using visual interpretation methods applied to digital elevation models (DEMs) derived from light detection and ranging (LiDAR) data. Surficial geology in BLUE was field mapped using GPS, following definitions and characterizations for surficial geology units established with the guidance of Dr. J. Steven Kite. A 2m x 2m LiDAR-derived DEM was used for BLUE and most of NERI using US Army Corps of Engineers (USCOE) LiDAR data, …
A Machine Learning And Data-Driven Prediction And Inversion Of Reservoir Brittleness From Geophysical Logs And Seismic Signals: A Case Study In Southwest Pennsylvania, Central Appalachian Basin, Tobi Micheal Ore
Graduate Theses, Dissertations, and Problem Reports (ETD)
In unconventional reservoir sweet-spot identification, brittleness is an important parameter that is used as an easiness measure of production from low permeability reservoirs. In shaly reservoirs, production is realized from hydraulic fracturing, which depends on how brittle the rock is–as it opens natural fractures and also creates new fractures. A measure of brittleness, brittleness index, is obtained through elastic properties of the rock. In practice, problems arise using this method to predict brittleness because of the limited availability of elastic logs.
To address this issue, machine learning techniques are adopted to predict brittleness at well locations from readily available geophysical …
Evolution Of Extreme Continental Saline Environments: A Sedimentological Investigation Of Permo-Triassic Redbeds And Evaporites In Northern Ireland And Kansas, Anna Sofia S. Andeskie
Evolution Of Extreme Continental Saline Environments: A Sedimentological Investigation Of Permo-Triassic Redbeds And Evaporites In Northern Ireland And Kansas, Anna Sofia S. Andeskie
Graduate Theses, Dissertations, and Problem Reports (ETD)
The Permo-Triassic was a time of extreme environments, unusually warm and arid climates, and biotic crises. This study investigates Pangean environments and climate leading to extreme acid saline lake systems represented by the Permian Nippewalla Group of Kansas and the Triassic Mercia Mudstone Group of Northern Ireland. Sedimentological observations of the underlying rocks, the Permian Hutchinson Salt Member of Kansas and the Permian Belfast Harbour Evaporite Formation of Northern Ireland, help to understand trends in environmental and climatic conditions leading to these extreme environments. This dissertation also refines the geographic extent of extreme acid saline lake and groundwater systems through …
Process Based Analysis Of Fluvial Stratigraphic Record: Middle Pennsylvanian Allegheny Formation, North-Central Wv, Oluwasegun O. Abatan
Process Based Analysis Of Fluvial Stratigraphic Record: Middle Pennsylvanian Allegheny Formation, North-Central Wv, Oluwasegun O. Abatan
Graduate Theses, Dissertations, and Problem Reports (ETD)
Fluvial deposits represent some of the best hydrocarbon reservoirs, but the quality of fluvial reservoirs varies depending on the reservoir architecture, which is controlled by allogenic and autogenic processes. Allogenic controls, including paleoclimate, tectonics, and glacio-eustasy, have long been debated as dominant controls in the deposition of fluvial strata. However, recent research has questioned the validity of this cyclicity and may indicate major influence from autogenic controls. To further investigate allogenic controls on stratal order, I analyzed the facies architecture, geomorphology, paleohydrology, and the stratigraphic framework of the Middle Pennsylvanian Allegheny Formation (MPAF), a fluvial depositional system in the Appalachian …
Relating Sonic Velocities, Minimum Horizontal Stress, And Natural Fracture Distribution To Stimulation Efficiency During Completion Of The Marcellus Shale Mip-3h Unconventional Well, West Virginia, Usa, Kaitlin Gayle Evans
Graduate Theses, Dissertations, and Problem Reports (ETD)
Log data from the Marcellus Shale Energy and Environment Laboratory (MSEEL) was acquired along the lateral of the MIP-3H well. This unconventional shale-gas well was completed within the Marcellus Shale just above the Cherry Valley Limestone, a thin limestone member separating organic rich units of the Marcellus. The geomechanical moduli, Poisson’s Ratio (PR) and Young’s Modulus (YME), were generated using compressional and shear sonic logs to indicate zones of increasing brittleness for each of the 28 stages along the 6124 ft. (1867m) horizontal lateral. Brittle reservoir rock is more readily fractured during hydraulic stimulation than more malleable rock. Stages with …
Reservoir Characterization And Static Earth Modeling For Potential Co2 Storage In Upper Pennsylvanian Cyclothems Of Midcontinent, Usa, Valerie Lynn Smith
Reservoir Characterization And Static Earth Modeling For Potential Co2 Storage In Upper Pennsylvanian Cyclothems Of Midcontinent, Usa, Valerie Lynn Smith
Graduate Theses, Dissertations, and Problem Reports (ETD)
This dissertation details the estimation of CO2 storage volume using reservoir characterization and the building of static earth models in two papers: 1) for Sleepy Hollow Field in Red Willow County, Nebraska and, 2) for Huffstutter Field, Phillips County, Kansas. These models are used to obtain estimates of CO2 storage capacity in stacked carbonate intervals of the Pennsylvanian Lansing and Kansas City groups (LKC). The LKC constitutes a regional succession of interbedded carbonates and shales. Located over the Cambridge Arch of Nebraska, these interbedded units were evaluated for carbon storage potential. Understanding the occurrence of carbonate porosity among …
First Description Of Subglacial Megalineations From The Late Paleozoic Ice Age In Southern Africa., Graham Dm Andrews, Andrew T. Mcgrady, Shannon M. Maynard
First Description Of Subglacial Megalineations From The Late Paleozoic Ice Age In Southern Africa., Graham Dm Andrews, Andrew T. Mcgrady, Shannon M. Maynard
Faculty & Staff Scholarship
We identify late Paleozoic ice age (LPIA) subglacial megalineations from field and geospatial imagery of the Twyfelfontein area of northern Namibia, and present the results of a geomorphometric analysis of those data. Asymmetric 0.1–1.5 km-long megawhalebacks indicate a paleo-ice flow to the northwest. We infer that an ice stream draining the LPIA Kaokoveld ice sheet existed within the proto-Huab River valley and that was comparable to ice streams in modern Antarctica. Recognition of a paleo-ice stream in northern Namibia supports interpretations of glaciogenic sedimentary successions (Itararé Group) in southern Brazil that suggest the presence of major, terrestrial glacial outlet systems …
How To Search For Life In Martian Chemical Sediments And Their Fluid And Solid Inclusions Using Petrographic And Spectroscopic Methods, Kathleen C. Benison
How To Search For Life In Martian Chemical Sediments And Their Fluid And Solid Inclusions Using Petrographic And Spectroscopic Methods, Kathleen C. Benison
Faculty & Staff Scholarship
Abundant resources and efforts have been employed in the search for life on Mars. Satellites, landers, and rovers have tested atmospheric gases, general sediment and rock compositions, and images of Mars surface in an effort to detect biosignatures left by any possible modern or ancient life. Chloride and sulfate minerals suggestive of past acid saline lakes have been found on Mars. In terrestrial acid brine environments, these minerals trap microorganisms and organic compounds and preserve them within fluid inclusions and as solid inclusions for long geologic time periods. Some cells remain viable, especially in the isolated, microscopic aqueous environments of …
Large-Area, High Spatial Resolution Land Cover Mapping Using Random Forests, Geobia, And Naip Orthophotography: Findings And Recommendations, Aaron E. Maxwell, Michael P. Strager, Timothy A. Warner, Christopher A. Ramezan, Alice N. Morgan, Cameron E. Pauley
Large-Area, High Spatial Resolution Land Cover Mapping Using Random Forests, Geobia, And Naip Orthophotography: Findings And Recommendations, Aaron E. Maxwell, Michael P. Strager, Timothy A. Warner, Christopher A. Ramezan, Alice N. Morgan, Cameron E. Pauley
Faculty & Staff Scholarship
Despite the need for quality land cover information, large-area, high spatial resolution land cover mapping has proven to be a difficult task for a variety of reasons including large data volumes, complexity of developing training and validation datasets, data availability, and heterogeneity in data and landscape conditions. We investigate the use of geographic object-based image analysis (GEOBIA), random forest (RF) machine learning, and National Agriculture Imagery Program (NAIP) orthophotography for mapping general land cover across the entire state of West Virginia, USA, an area of roughly 62,000 km2. We obtained an overall accuracy of 96.7% and a Kappa statistic of …
Protoconch Enlargement In Western Atlantic Turritelline Gastropod Species Following The Closure Of The Central American Seaway, Stephanie Sang, Dana Suzanne Friend, Warren Douglas Allmon, Brendan Matthew Anderson
Protoconch Enlargement In Western Atlantic Turritelline Gastropod Species Following The Closure Of The Central American Seaway, Stephanie Sang, Dana Suzanne Friend, Warren Douglas Allmon, Brendan Matthew Anderson
Faculty & Staff Scholarship
Abstract The closure of the late Neogene interoceanic seaways between the Western Atlantic (WA) and Tropical Eastern Pacific (TEP)—commonly referred to as the Central American Seaway—significantly decreased nutrient supply in the WA compared to the TEP. In marine invertebrates, an increase in parental investment is expected to be selectively favored in nutrient‐poor marine environments as prolonged feeding in the plankton becomes less reliable. Here, we examine turritelline gastropods, which were abundant and diverse across this region during the Neogene and serve as important paleoenvironmental proxies, and test whether species exhibit decreased planktotro‐ phy in the WA postclosure as compared to …
Submarine Groundwater Discharge Data At Meter Scale (223ra, 224ra, 226ra, 228ra And 222rn) In Indian River Bay (Delaware, Us), Carlos Duque, Karen L. Knee, Christopher J. Russoniello, Mahmound Sherif, Usama A. Abu Risha, Neil C. Sturchio, Holly A. Michael
Submarine Groundwater Discharge Data At Meter Scale (223ra, 224ra, 226ra, 228ra And 222rn) In Indian River Bay (Delaware, Us), Carlos Duque, Karen L. Knee, Christopher J. Russoniello, Mahmound Sherif, Usama A. Abu Risha, Neil C. Sturchio, Holly A. Michael
Faculty & Staff Scholarship
Abstract
Submarine groundwater discharge (SGD) was sampled at high-spatial resolution in Indian River Bay, DE, USA, in July 2016 to characterize the spatial variability of the activity of the radium and radon isotopes commonly used to estimate SGD. These data were part of an investigation into the methods and challenges of characterizing SGD rates and variability, especially in the coastal aquifer transition from freshwater to saltwater (Hydrogeological processes and near shore spatial variability of radium and radon isotopes for the characterization of submarine groundwater discharge (Duque et al., 2019)). Samples were collected with seepage meters and minipiezometers to obtain sufficient …
Geochronology And Depositional History Of The Sandy Springs Aeolian Landscape In The Unglaciated Upper Ohio River Valley, United States, Mathew P. Purtill, J. Steven Kite, Steven L. Forman
Geochronology And Depositional History Of The Sandy Springs Aeolian Landscape In The Unglaciated Upper Ohio River Valley, United States, Mathew P. Purtill, J. Steven Kite, Steven L. Forman
Faculty & Staff Scholarship
The study of active and stabilized late Quaternary aeolian landforms provides important proxies for past climate events and environmental transitions. Despite an overall increase in the study of aeolian landforms in previously glaciated and coastal settings in eastern North America, the history of aeolian sedimentation in many unglaciated inland alluvial settings remain poorly understood. This study reports on the geochronology and depositional history of aeolian landforms and sediments in the unglaciated upper Ohio Valley at the Sandy Springs site. Aeolian landforms and sediments include complex, linear, barchan-like, and climbing dunes; an interdune sand sheet; and sandy loess that blankets high …
Utilizing Lipid Biomarkers To Understand The Microbial Community Structure Of Deep Subsurface Black Shale Formations, Rawlings Akondi
Utilizing Lipid Biomarkers To Understand The Microbial Community Structure Of Deep Subsurface Black Shale Formations, Rawlings Akondi
Graduate Theses, Dissertations, and Problem Reports (ETD)
The deep subsurface environment has been known to host microbes as early as 1926 and has also been suggested to potentially account for as much as 50% of the Earth`s biomass. Researchers have shown that microbes alter their membrane lipid components in response to physiological stress, producing stress indicative lipid biomarkers. However, little effort has been made to understand the subsurface microbial community of the shale ecosystem which is increasingly being exploited and altered by addition of drilling and hydraulic fluids to meet our growing energy needs. Phospholipid fatty acids (PLFAs) are microbial lipid biomarkers and are found in all …
Petrophysical And Geomechanical Characterization Of The Marcellus Shale In The Appalachian Basin, Yixuan Zhu
Petrophysical And Geomechanical Characterization Of The Marcellus Shale In The Appalachian Basin, Yixuan Zhu
Graduate Theses, Dissertations, and Problem Reports (ETD)
In recent years, more and more attention is paid to shale gas and hydrocarbon liquids exploration and exploitation in unconventional reservoirs. With the development of horizontal drilling and hydraulic fracturing, production from unconventional reservoirs has been greatly increased. However, not all wells, regions and basins harbor highly successful shale gas and liquids producers. In order to improve the production efficiency and reduce the cost of projects, detailed analysis needs to be undertaken to characterize the reservoir. As opposed to conventional reservoirs, extraction of gas in the unconventional reservoir is dependent not only on the reservoir quality, but also on completion …
Structural Style And Stratigraphic Architecture Of The Northeastern Brooks Range, Alaska, Benjamin G. Johnson
Structural Style And Stratigraphic Architecture Of The Northeastern Brooks Range, Alaska, Benjamin G. Johnson
Graduate Theses, Dissertations, and Problem Reports (ETD)
The Arctic Alaska–Chukotka microplate is a large Mesozoic–Cenozoic composite terrane that resides at the northern limit of the North American Cordillera. Although its Mesozoic origins are assuredly linked to the opening of the Amerasian Basin of the Arctic Ocean, its Paleozoic origins can be linked to at least three separate paleocontinents, including northern Laurentia, Baltica, and Siberia. Across the Arctic Alaska portion of the microplate, an internal, mid-Paleozoic suture zone presumably separates rocks of the North Slope subterrane (Laurentian affinity) from a collection of smaller subterranes in the southern Brooks Range and Seward Peninsula (Baltic affinity).
The mountains of the …
Beneath The Gypsum Dunes: Cenozoic History Of Wind And Water From A Core Drilled At White Sands, New Mexico, Jackson Bentley Jakeway
Beneath The Gypsum Dunes: Cenozoic History Of Wind And Water From A Core Drilled At White Sands, New Mexico, Jackson Bentley Jakeway
Graduate Theses, Dissertations, and Problem Reports (ETD)
White Sands, New Mexico is the largest gypsum dune field on planet Earth, the result of reworking of gypsum deposits. The dunes have been well studied, but the Cenozoic history preceding the formation of the dune field has been poorly studied. A core drilled to a depth of 192 ft (58.5 m) beneath the modern dune field contains deposits from saline lakes, sandflats, perennial freshwater lakes, perennial brackish to saline lakes, and saline mudflats.
The core is composed of bottom-growth bedded gypsum, gypsum sandstone and siltstone, mixed siliciclastic-gypsum sandstones and siltstones, laminated siliciclastic mudstones, gypsum mudstones, and carbonate mudstones. Bottom-growth …